Sweetener solutions as binding agents for amaranth bars: evolution of temporal dominance of sensory attributes

The objective of the study was to determine the effects of replacing binding agents with commercial low-calorie sweetener solutions on the physicochemical and temporal dominance of sensations in amaranth bars. Five baked amaranth bar formulations (Sweetener-Solution-Formulated Amaranth Bars: SSFABs) were prepared using solutions of erythritol, sucralose, steviol and two sucrose concentrations (50% and 25%). A commercial bar (COMM) was used as a control. Proximal, pH, water activity, texture and colour were measured. Temporal dominance of sensations (TDS) was used to determine dominant attributes in time. In general, SSFABs showed a higher moisture, ash and protein content compared to COMM. Carbohydrates and total crude fat were lower in SSFABs than in COMM. Dominant attributes were Crispy, Dry, Sweet and Amaranth. Erythritol formulation was similar to the commercial bar in terms of maximum dominance rate. Replacement of binding agents impacted on the evolution of dominant attributes in amaranth bars.     

MECHANISMS UNDERLYING THE ROLE OF FRICTION IN ORAL TEXTURE

The role of friction in food texture sensations are reviewed with the focus on results from our own laboratory, concentrating on texture sensations that are affected by the lubricative properties (e.g., roughness and creaminess), by the viscosity (e.g., melting and thickness) and by the used thickeners (e.g., airiness and heterogeneity). A food's lubricative properties are affected by its fat content, fat droplet size, particle size and shape and thickener. Foods with lower fat contents, larger fat droplets, larger particles and specific thickeners exhibited higher friction while their creaminess and fattiness sensations, associated with good lubrication, are reduced. Roughness and dryness sensations, associated with poor lubrication, are increased. Taste and flavor compounds also affected these texture sensations, albeit via a different mechanism. Specific compounds can affect the lubricative properties of saliva resulting in friction‐related sensations, such as astringency. Astringent compounds interact with proline‐rich proteins in saliva, causing precipitation that may be sensed as discrete particles and/or increased roughness. Alternatively, the compounds may precipitate dead cells and other debris present in saliva. Astringent compounds may also directly affect the surface properties of the oral mucosa.     

Analysis for Flavor Residuals in the Mouth by Gas Chromatography

Analyses for trace flavorants in the mouth were performed by extraction of aqueous mouth rinses with methylene chloride, concentration of the extract, and gas chromatographic analysis of the concentrate. Trace flavorants were determined after chewing peppermint-flavored gum and after rinsing with mouthwashes. The durability of several flavorants in the mouth was compared. The data obtained show that flavorants differ in their retainability in the mouth, as judged from the amount of their residuals. Menthol and anethole are retained longer than most common flavorants. Flavor esters are partially hydrolyzed in the mouth to give the corresponding alcohols. Aldehydes are also affected and produce their corresponding alcohols.     

The role of friction in perceived oral texture

Instrumentally measured in vitro friction in semi-solid foods was related to oral texture sensations. Increased fat content resulted in lower sensations of roughness, higher sensations of creaminess, and lower friction, suggesting that lubrication is the mechanism by which fat affects oral texture in low fat foods. Starch breakdown by salivary amylase in low fat foods resulted in reduced friction, possibly through the release of fat from the starch food matrix, and the migration of fat to the surface of the bolus where it becomes available for lubrication. No evidence was found that salivary mucins or salivary viscosity play a role in lubrication. Astringent sensations may be related to reduced lubrication and increased friction caused by particles, either resulting from precipitation of salivary protein rich proteins or from flocculation of dead cells.     

Strategies to compensate for undesired gritty sensations in foods

This study investigated whether the addition of macroparticles or fat can be used to compensate for negative texture sensations in quark. Cellulose beads were added as model microparticles (1.5% w/w; average size: 263 µm) to quark (0% fat) to induce unpleasant gritty sensations. The addition of microparticles to quark significantly increased grittiness and dryness, while creaminess and liking decreased. Three strategies were explored to reduce the impact of unpleasant gritty sensations on consumer perception: two strategies involved the addition of macroparticles (granola or peach gel pieces); the third one consisted of increasing the fat content of the quark (4.4 and 8.8% w/w). For all three strategies, grittiness caused by microparticles did not significantly decrease when macroparticles or fat were present. Addition of peach gel pieces to quark with microparticles did not increase liking. When granola pieces were added to quark containing microparticles, liking increased significantly despite that grittiness was still perceived. Temporal Dominance of Sensations (TDS) revealed that addition of granola pieces caused prolonged dominance of positive, crunchy sensations and minimized dominance of negative, gritty sensations. The addition of fat did not lead to a significant increase in liking of quark, although when a medium amount of fat was added (4.4%), it also did not decrease liking significantly. This was probably due to an effective hedonic compensation triggered by more positive sensations (i.e. sweetness). We conclude that addition of crunchy granola pieces or fat can be used as strategies to shift and increase dominance of positive and liked attributes, leading to an increase of overall liking, although negative sensations (grittiness) caused by microparticles are still perceived. This approach could be used to compensate for undesired texture sensations in different types of foods, such as high protein foods.     

PROP sensitivity reflects sensory discrimination between custard desserts

Sensitivity to 6-n-propylthiouracil (PROP) for a group of 180 naïve consumers was related to their perception of 16 commercially available vanilla custard desserts. Rated intensities of taste and texture attributes varied moderately and inconsistently with PROP sensitivity. In contrast, discriminative ability increased with PROP sensitivity resulting in higher numbers of significant differences between pairs of custards. In terms of signal/noise theory, the results indicate that PROP sensitivity enhances the separation of the response signals but does not reduce their noise. The naïve consumers were also compared with highly trained panelists to test whether effects of PROP sensitivity resemble the effects of experience and training. Naïve consumers and trained panelists responded similarly with respect to taste and texture sensations such as creaminess and thickness, but were clearly different with respect to others such as heterogeneity and fattiness. Trained panelists demonstrated even stronger discriminative abilities than consumers with high PROP sensitivities for some attributes but weaker abilities for others. A practical implication of these findings is that selection criteria for participation in sensory panels should include PROP sensitivity, if the panel is aimed at maximum discriminative performance.     

Investigating temporal sensory data via a graph theoretic approach

A graph theoretic approach is applied to investigate perception dynamics in the Sensometrics 2018 Data Analysis Workshop data sets. First, temporal check-all-that-apply (TCATA) data are investigated: ten sensory attributes are modelled as vertices and concurrent perception as edges, the size and width of each corresponding to the momentary elicitations and the concurrent elicitations, respectively. A temporal dominance of sensations (TDS) data set does not lend itself as readily to this type of analysis because the task for each assessor involves selection of only one dominant attributes at a time. For this reason, TDS data sets considered in this workshop are (re-)analyzed within localized temporal ranges, considering dominance elicitations within localized temporal ranges to be adjacent-dominant. In TDS by Modality (M-TDS), assessors taste the sample to evaluate the five taste and flavour attributes via TDS, then retaste the sample to evaluate the five texture attributes via TDS. M-TDS results from these two separate tasting timelines are adjoined as if they arose from a single evaluation timeline, which ignores systematic biases that may be introduced by the evaluation protocol (e.g. texture attributes are always evaluated with carryover effects from the first tasting). Data from each of these temporal sensory method are then analyzed using a graph theoretic approach. Cliques and attribute structures are identified. TCATA and TDS results are more similar to one another than either is to M-TDS results. Implications of method choice and various data pre-processing decisions are discussed.     

ORAL PHYSIOLOGY AND TEXTURE PERCEPTION OF SEMISOLIDS

ABSTRACT

In the oral cavity, the food is subjected to several mechanical and chemical processes. It is fractured by the teeth, diluted and broken down by saliva, heated or cooled by the ambient temperature of the mouth, formed into a bolus and finally swallowed. Numerous receptors in the oral cavity and nose respond to the initially ingested food and monitor the changes during processing. This leads to central perceptions of taste, odor, irritation and texture of the food. Most sensations associated with food texture occur only when the food is manipulated, deformed or moved across the oral receptors. In addition, people assessing the same stimulus differ in their ratings of that stimulus and their oral physiological parameters also exhibit inter‐individual variations. This paper is based on the PhD thesis of one of the authors. It gives an overview of this study and includes related work of other authors. The aim of our research was to improve the understanding of oral texture perception, in particular to examine the role of oral physiological processes in oral texture perception of semisolids and to investigate whether individual differences in perception could be attributed to differences in oral physiology among subjects. The results of our study demonstrate that oral physiological parameters such as oral sensitivity, tongue movements, temperature and saliva composition are of importance for texture perception of semisolids. Many parameters of oral physiology correlate with various perceived texture attributes. This implies that intra‐individual differences in texture perception could be attributed to variations in oral physiology. Oral physiology thus plays a role in texture perception of semisolids and should be taken into account in future texture research.

PRACTICAL APPLICATIONS

By understanding the processes in the mouth while eating, a better understanding of the sensations and the perceptions of the food can be gained. Taking for each food the relevant physiological parameter into consideration when performing and designing rheological/instrumental measurements grants more natural conditions and better predictions of sensory perception. This could save time and money on time‐consuming and expensive sensory panels in the earlier steps of product development and renovation. Knowing how physiological processes highlight specific flavor/texture sensations may be useful for product development or quality control where one typically wants to focus on certain sensations and ignores others. In addition, a future application could be to tailor products for personalized nutrition, individual choices or clinical nutrition based on physiological groups.     

A quantitative information measure applied to texture perception attributes during mastication

We have calculated an entropy or information measure of previously reported experimentally determined temporal dominance of sensations (TDS) data of texture attributes for two sets of emulsion filled gels throughout the mastication cycle. The samples were emulsion filled gels and two-layered emulsion filled gels. We find that the entropy measure follows an average curve, which is different for each set. The specifics of the entropy curve may serve as a fingerprint for the perception of a specific food sample.     

Prediction of sensory attributes of cheese by near-infrared spectroscopy

The objective of this work is to evaluate by near infrared reflectance (NIR) spectroscopy different attributes, visual (presence of holes), taste (salty, buttery flavour), texture (hardness, chewiness, creamy), rancid flavour and other sensations (pungency, retronasal sensation), in cheeses elaborated with milk of variable composition (cow, ewe, goat), collected in winter and summer and subject to ripening times of 4 and 6 months, taking as reference data the evaluation of the sensorial properties obtained by a panel of eight trained experts.     

Trace Components of the Flavor Fraction of Maple Syrup

SUMMARY– An exhaustive chloroform extraction of maple syrup removed the maple flavorants. The extract was analyzed in part by a gas chromatograph-mass spectrometer tandem procedure. Several previously undetected flavor-related compounds were found in trace amounts. Among these were the aromatic compounds acetovanillone, guaiacyl acetone and vanilloyl methyl ketone. These aromatics could have resulted from the ethanolysis of ligneous material previously reported in maple sap. Sugar degradation products found were furfural, hydroxymethylfurfural, lactic acid and levulinic acid. These indicate that the products of caramelization also are part of the maple flavorants.
Acids found, in addition to those above, were the C₅ to C₉ aliphatic acids and oxalic, fumaric and malic acids. All of the acid occurred as ethyl esters resulting from unintentional esterification during extraction. The C, to C, acids may be artifacts perhaps derived from the vegetable oil used as antifoaming agent in syrup processing.     

Relating Creamy Perception of Whey Protein Enriched Yogurt Systems to Instrumental Data by Means of Multivariate Data Analysis

Yogurts differing in fat content, protein content, and casein to whey protein ratio were produced, and structurally as well as sensorially examined. The objective of the current research was to evaluate the predictive value of rheological and particle size measurements concerning sensory appearance and texture attributes in 13 differently composed stirred yogurt systems, with a focus on graininess, viscosity, and creaminess. Structural and sensory analyses showed large differences in texture properties between the tested yogurt systems. Both data sets were correlated by means of multivariate statistical methods. Sensory graininess was highly correlated with particle size‐related parameters, sensory viscosity was highly correlated with destructive rheological parameters, and creamy perception was highly correlated with particle size‐related parameters and destructive rheological parameters but was not as well described by any oscillatory parameter. Best predictive ability (r² > 0.89) was found for creaminess combining particle size related‐ and destructive rheological parameters tested within this study. Practical Application : Knowing the instrumental parameters describing sensory textural attributes provides important information for having a better understanding of the underlying processes during consumer's perception. Knowledge about the sensory behavior of a product and its oral processing imparts an opportunity to fasten the product development process. By means of yogurt systems instrumental parameters derived from particle size analysis and rheological measurements were correlated with sensory attributes in order to determine the main factors leading to the mouthfeel sensations grainy, viscous, and creamy of semisolid milk products.